NEW YORK — Despite President Donald Trump’s threats to blow it up, the Iran nuclear deal still has a “better than 50” percent chance of surviving the next year, Iranian Foreign Minister Mohammad Javad Zarif told POLITICO in an extensive interview detailing how his country will — and won’t — respond to Trump’s extraordinary campaign against the agreement the American president calls “an embarrassment to the United States.”

Zarif called Trump’s harsh attack on Iran in his recent U.N. speech “the most insulting statement that had ever been made by any U.S. president against Iran since the Revolution.” But he said it has backfired, isolating the United States and undermining its credibility “as a reliable negotiating partner” on the world stage, and he vowed not to renegotiate the nuclear deal. If Trump tried to unravel it, Zarif said in the interview for The Global Politico, our weekly podcast on world affairs, Iran would consider everything from “walking away from the deal to somehow accommodating Europe.”

Spend an hour with Zarif, the American-educated diplomat who brokered the agreement two years ago with Barack Obama’s administration and five other major world powers, and it’s clear that he thinks Iran bested Trump at the U.N. over the last couple of weeks.

After all,Trump publicly widened the rift with European allies even as his Secretary of State Rex Tillerson failed to persuade them privately — or even make a coherent case — for blowing up the nuclear accord, potentially doing long-term damage to the U.S. ability to cut deals with any number of global bad actors. “The Europeans have made it very clear to us and to the United States that they intend to do their utmost to ensure survival of the deal,” Zarif said, using some of his strongest public language yet for a series of backstage meetings that made clear what a striking gap Trump has opened up between the Americans and their closest allies.

Zarif’s stinging comments about Trump’s efforts come at a key decision point on Iran for the president and Tillerson. While the Iran deal crisis has been publicly overshadowed in recent days by the president’s war of words with nuclear-armed North Korea, it has provoked a major behind-the-scenes battle pitting an increasingly isolated Tillerson against other Trump advisers ahead of an October 15 deadline for the president to certify Iran’s compliance with the deal — or send the issue back to Congress.

Tillerson, whom Trump publicly smacked down on Twitter Sunday over his efforts to open back-channel talks with the North Koreans, has waged a lonely fight against “decertification” of the Iran deal as well, according to several of those I spoke with who have been briefed on the internal debates and expect the president to overrule the secretary on this too.

“Tillerson is still trying to convince Trump,” said a key outside adviser to the White House. Another source briefed on the deliberations in the Pentagon and State Department said Tillerson had support there but not in the White House — and even those who disagree with decertification “are now adjusting to the reality it is going to happen.” They are “negotiating over the wording” Trump will use, this source said, and the framing of the decision, which is likely to be accompanied by the rollout of what the White House is billing as a “major new strategy” to combat malign Iranian influence across the Middle East.

In the interview, Zarif acknowledged that Trump has now created the expectation that he will refuse to recertify the nuclear deal — while noting pointedly that Trump could still flip-flop on this, just as he has in so many other cases. “This would not be the first time that President Trump or other presidents have walked back from positions that they have taken during the campaign,” he said.

"You’ve seen U.S. allies saying that the United States is not a reliable partner" — Javad Zarif

Decertification by itself would not rip up the deal and Zarif noted that the Republican-controlled U.S. Congress could decide — as it has in the past — not to take any action following through on Trump’s rhetoric. Doing nothing would effectively leave the deal in place, Zarif argued, and besides is essentially what he calls an “internal” U.S. affair, since technically the nuclear accord is a U.N. Security Council resolution and not a congressional one anyway.“It’s up to Congress to adopt any decision, or not to adopt any decision, and I believe in the past a Republican Congress had this idea to let the nuclear agreement stay, as did our parliament,” Zarif said. “It had decided in the past not to take action; it can decide again.”

Throughout the lengthy conversation in the wood-paneled reception room of the faded Upper East Side mansion that serves as Iran’s U.N. headquarters, Zarif was unsparing in his critique of Trump. At various points, he bemoaned the American president’s “posturing,” called out his “alternative facts” as “publicity stunts,” lamented his “insulting” words and his “disappointing” position, worried about his “frightening” showdown with North Korea, and agreed with those who argue that Trump’s overheated rhetoric has now made it easier rather than harder for Iran to command sympathy in the international arena.

“Now, look at the message that you are sending to the world,” Zarif said. “It would make it tougher for anybody to believe and rely upon the United States — anybody, not just North Korea. You’ve seen U.S. allies saying that the United States is not a reliable partner.”

But it was equally striking what Zarif did not say. There was no Kim Jong Un-like retaliatory rhetoric, no “Death to America”-type rants so familiar from past Iranian leaders. Instead, both Zarif and Iranian President Hassan Rouhani were relatively restrained in their immediate response to Trump’s U.N. speech — Rouhani chose only to add three sentences to his U.N. address that did not mention Trump by name while warning of the hot-headed actions of a “rogue newcomer,” and Zarif tweeted that it was “unworthy of a reply.”

Susan B. Glasser interviews Javad Zarif | Bridget Mulachy/POLITICO

As much as anything, their response seemed to reflect Zarif’s determination not to undercut the strong position the Iranians believe Trump has placed them in. “They think Trump has played into their hands the way he has gone after the deal,” said another former U.S. official who has spoken with Zarif in recent days.

At one point, I asked him whether Iran would also walk away from the deal if Trump went ahead with his threat to do so.

“No, no, no,” Zarif said, at least not right away, what with Europe indicating it will stick with it and with Congress yet to act. “We will wait.”

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Ever since becoming President Rouhani’s foreign minister four years ago, Javad Zarif — a fluent English speaker whose international relations training came at the same Colorado graduate school that also turned out future Secretary of State Condoleezza Rice — has been the West’s favored Iranian interlocutor.

He and Rouhani, who was just reelected to another presidential term, are seen as Iran’s leading moderates, and both have staked their jobs on the survival and success of the nuclear deal they struck with the United States, Russia, China, Great Britain, France, and Germany in 2015. Zarif today remains the “unflappable,” “unflustered,” “smart and charming” but also persnickety and at times even “petulant” negotiator who haggled with the Americans over every detail, as a one-time aide to his negotiating partner, former Secretary of State John Kerry, described him to me the other day.

But he is also seen as “the master of reading what people here — in his mind — ought to hear,” said another former senior U.S official whose brief included Iran. “He is smart, worldly and comes across as eminently reasonable.”

There’s just one problem, the official said: “Too bad he doesn’t make Iran’s policies, especially in its region.”

That view is widespread in Washington, where most analysts consider hard-liners associated with Supreme Leader Ayatollah Ali Khamenei and the Iranian Revolutionary Guards the true decision-makers in Iran. Even supporters of the Iran nuclear deal find Zarif at times a frustrating adversary — and most debate in the U.S. foreign policy circles of both parties tends to be over how to punish Iran’s bad behavior, not whether it exists.

All of which makes it more than a little jarring to talk about the politics of the Iran deal with Zarif in the midst of this latest crisis: He is the man in the middle of the international efforts to save the deal he cut, but appears to hold little sway over most of the other disputes that Washington and others have with his country, from the ongoing development of ballistic missiles that could eventually be used to deliver a nuclear warhead to backing for the murderous regime of Syria’s Bashar al-Assad and support for Shiite proxy militias across the region.

On the one hand, Zarif clearly has a strong case to make for his grievance about Trump’s questioning of the nuclear deal.

The International Atomic Energy Agency has repeatedly certified that Iran is complying with the terms of the Joint Comprehensive Plan of Action, or JCPOA, as the nuclear deal is formally known. Even Trump officials such as Tillerson and Joint Chiefs of Staff chairman General Joseph Dunford have publicly acknowledged in recent days that Iran is not only in “technical compliance” but that undoing the deal now would, as Dunford put it in congressional testimony,, undercut future diplomacy with North Korea and others.

Zarif did not say why Iran is still developing longer-range ballistic missiles — only that doing so does not violate the technical language of the nuclear agreement.

“It makes sense to me that our holding up agreements that we have signed, unless there is a material breach, would have an impact on others’ willingness to sign agreements,” Dunford said, in a little-noticed rebuke of the president last week.

But if Zarif is on solid ground on the letter of the nuclear deal itself, he’s much shakier when it comes to defending Iran’s actual behavior.

Trump and American foreign policy hands in both parties view Iran as a destabilizing factor in the Middle East, allied with Russia and other problematic allies like Syria’s Assad. Didn’t he regret the enormous death toll in the Syrian civil war, I asked Zarif, where Iranian fighters and proxy militias have fought alongside Russians to keep Assad in power even as nearly half a million Syrians have been killed and millions more have been displaced from their homes?

Zarif would hardly answer, instead deflecting blame on those who failed to consider conditions for peace talks he laid out four years ago.

And what about Assad’s use of chemical weapons on his own people, a repeatedly documented fact even after Assad cut a deal with the international community to supposedly remove those weapons?

An Iranian woman walks past a mural on the wall of the former U.S. embassy in the Iranian capital Tehran | Atta Kenare/AFP via Getty Images

Iran, a victim of major chemical attacks by Iraqi leader Saddam Hussein’s forces during Iran-Iraq war of the 1980s, has long spoken out against the use of such weapons in other contexts. But in this, Zarif merely restated Iran’s talking points, demanding a U.N. investigation and blaming “the United States and its allies” who “prevented” it.

He did not say, in our interview or in others he held over the last couple weeks, why Iran is still developing longer-range ballistic missiles — only that doing so does not violate the technical language of the nuclear agreement.

And more broadly, he left me uncertain as to why he would not consider negotiations with Trump at all — given that Iran also has many grievances, including what it sees, with some legitimacy, as less-than-robust U.S. compliance with those aspects of the deal that are supposed to offer economic benefits to Iran.

“I think they don’t quite know what to do with Trump other than just basically say no to everything,” said one of the former U.S. officials who has spoken to Zarif in recent days.

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In the end, the fight over the Iran deal may well depend on how correctly Zarif, his country’s designated America-whisperer, reads America’s volatile new president.

And he claims to have a pretty good fix on the place.

“I predicted Trump’s victory,” he tells me after we finished recording the podcast. He went on to recount how he had to overrule his staff at the Iranian foreign ministry after they prepared analyses of the 2016 election that only accounted for a Hillary Clinton victory. He also said he warned Mexico’s foreign minister at the time that she was making a mistake by planning for a Clinton win.

How did you know Trump would score such a stunning upset?, I asked Zarif.

“It’s my job,” he said.

Susan B. Glasser is POLITICO’s chief international affairs columnist. Her new podcast, The Global Politico, comes out Mondays. Subscribe here. Follow her on Twitter @sbg1.